sea level rise betweem LGM and imtermediate glacial fields.pdf
The Last Glacial Maximum (LGM) Modified from: Royal Geographic Society: Glacial Landscapes Lesson 1.
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Transcript of The Last Glacial Maximum (LGM) Modified from: Royal Geographic Society: Glacial Landscapes Lesson 1.
The Last Glacial Maximum (LGM)
Modified from: Royal Geographic Society: Glacial Landscapes Lesson 1
What is the LGM?• Latest phase in Earth’s geologic history
(26,000-18,000 years ago) when the planet’s:–Average temperature reached a minimum–Area of land covered by glaciers and ice
sheets reached a maximum • ~3x more than currently present
–Sea-level was about 120 meters lower than present
Global Glacial Coverage During the LGM
Image Source: http://www.humberriver.ca/globalice.html
Glacial Coverage of North America
During the LGM Im
age
Sour
ce: I
daho
Mus
eum
of N
atur
al H
istor
y
Glacial Coverage of Europe During the LGM
Image Source: www.kids.britannica.com
• The edge of an ice cap in modern day Iceland–This may be
similar to what landmasses in the Northern Hemisphere looked like during the LGM D.E.Anderson
Extinct Animals & Ice Age Terrain
Image source: Wiki Commons
Glacial Cycles within the Quaternary
• Earth’s climate has oscillated between cold glacial times and warm interglacial periods–The LGM was the coldest part of the
most recent ‘glacial’ period–We are currently warming up from the
LGM and entering an interglacial period
Retreat of North
American Glaciers as the LGM
Ended
Animation Source: http://www.museum.state.il.us/exhibits/ice_ages/
Average globaltemp. changefrom today
The LGM
Our presentwarm time,the Holocene
These are twoice core basedtemp. reconstructionsfrom Antarctica
Image Source: Robert A. Rohde / Global Warming Art
Differences in Ice Sheet/Sea Ice Extent Between LGM and Today
Mark McCaffrey , NGDC/NOAA Source: http://www.ncdc.noaa.gov/paleo/slides/slideset/11/11_178_slide.html
LGM
LGM
Global Glacial CoverageLGM• About 30% of land was
covered by glaciers (>40 x 106 km2)
• Distribution of world’s glacial ice:– Antarctica: 30% – Greenland: 5%– Laurentide Ice Sheet
(northeastern - North America): ~30%
– Scandinavian Ice Sheet (northern Europe): ~15%
– Remainder of globe: ~20%
Present• About 10% of land was
covered by glaciers (~15 x 106 km2)
• Distribution of world’s glacial ice:– Antarctica: 85% – Greenland: 11%– Remainder of globe: 4%
Average Global TemperaturesPresent
• About 6°C colder– Much colder at high
latitudes– Slightly less nearer to the
Equator
LGM• Average: 14.6°C– Still colder at high
latitudes– Warmer nearer to the
Equator• Temperatures have risen
0.5°C since 1960s
Sea Level Change During the LGM• Dropped to about 120 meters below present
level – More of the world’s H20 was transferred from the
oceans to glacier ice
Eastern U.S. Coastline During the LGM
Image Source: PBS - NOVA: Mountain of Ice
Florida & Eastern Gulf of Mexico Coastline During the LGM
Image Source: PBS - NOVA: Mountain of Ice
Northern European Coastline During the LGM
Image Source: PBS - NOVA: Mountain of Ice
Southeast Asian Coastline During the LGM
Image Source: PBS - NOVA: Mountain of Ice